1. Field of the Invention
The present invention relates to a method and apparatus for cleaning exhaust gas exhausted from combustion equipment such as a boiler, incinerator, etc. and internal combustion engines such as a gasoline engine, diesel engine, etc.
2. Description of the Prior Art
The exhaust gas from internal combustion engines such as the gasoline engine, diesel engine, etc. contains various kinds of toxic substances. To improve the rate of fuel consumption and clean the exhaust gas, it has been proposed to use an exhaust gas cleaner using a catalyst, to attain a complete combustion of the fuel by electronically controlling the supply of air and fuel to the engine, etc.
To remove toxic components from the exhaust gas of combustion equipment such as a boiler, incinerator, etc., it has been proposed to use an apparatus which provides a complete combustion of fuel by automatic control of the combustion in the furnace, to provide a stack gas desulfurization and denitration facility, an electric precipitator, etc. in combination with the combustion, etc.
The exhaust gas from internal combustion engines contains carbon monoxide(CO), hydrocarbon(HC), nitrogen oxides(NO.sub.x), black smoke, etc. It is considered that such toxic components are caused to develop by any of the following:
(1) Incomplete combustion due to insufficient supply of air
(2) Dissociative thermo-reaction of carbon dioxide(CO.sub.2) and steam (H.sub.2 O) during combustion at an elevated temperature
(3) Generation of intermediate products during incomplete combustion
The combustion equipment such as a boiler, incinerator, etc. exhausts, together with a large volume of sulfur oxides (SO.sub.x) and nitrogen oxides(NO.sub.x) yielded from a fuel such as oil, coal or the like and coarse particulates and dust resulting from incomplete combustion of the fuel.
The conventional exhaust gas cleaner does not of remove the toxic components satisfactory. The exhaust gas cannot be effectively removed without a plurality of such cleaners in combination. The cleaners require a large space for installation and also large costs.